1245131857 has 2 divisors, whose sum is σ = 1245131858. Its totient is φ = 1245131856.

The previous prime is 1245131827. The next prime is 1245131977. The reversal of 1245131857 is 7581315421.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1175392656 + 69739201 = 34284^2 + 8351^2 .

It is an emirp because it is prime and its reverse (7581315421) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1245131857 - 2¹⁹ = 1244607569 is a prime.

It is not a weakly prime, because it can be changed into another prime (1245131827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 622565928 + 622565929.

It is an arithmetic number, because the mean of its divisors is an integer number (622565929).

Almost surely, 2^1245131857 is an apocalyptic number.

It is an amenable number.

1245131857 is a deficient number, since it is larger than the sum of its proper divisors (1).

1245131857 is an equidigital number, since it uses as much as digits as its factorization.

1245131857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 33600, while the sum is 37.

The square root of 1245131857 is about 35286.4259595669. The cubic root of 1245131857 is about 1075.8171128776.

The spelling of 1245131857 in words is "one billion, two hundred forty-five million, one hundred thirty-one thousand, eight hundred fifty-seven".